Pediatric fever is a self-protective mechanism to fight the disease by mobilizing the whole body’s immune system. Body temperature is closely related to the child’s physical condition, nutritional status, time (such as morning and evening, seasons), but not related to the severity of the disease, that is, not the higher the temperature, the more serious the disease, and sometimes repeated high fever for 3-5 days is very common, so in the process of fever reduction, we should actively seek treatment for the primary disease, do not simply one-dimensional fever reduction. I. When to apply antipyretics? Axillary more than 37.3 ° C (or 37.5 ° C), defined as fever. It is further divided into low fever 37.4~38°C; medium fever 38.1~39°C; high fever 39.1~41°C; and ultra-high fever: above 41°C. Fever of ≤1 week is considered acute fever. For patients with temperature below 38.5°C, if the mental state is good, antipyretic drugs can be withheld and physical cooling is sufficient. For patients over 38.5°C, antipyretic drugs should be applied to reduce energy consumption and avoid complications such as febrile convulsions. The World Health Organization (WHO) recommends two classic oral antipyretics that are safe for pediatric use: acetaminophen and ibuprofen. 1.Acetaminophen(Paracetamol,Tylenol): First choice, for children over 3 months old. Routine dosage for children: oral, 10-15mg/kg/times, once every 4-6h; children aged 3-12 years old should be applied less than 5 times every 24h, and the course of treatment should not be more than 5d. Rectal administration is no longer recommended for pediatric application. Acetaminophen is safe at reasonable doses, with occasional nausea, vomiting, sweating, and abdominal pain, and a few cases of dermatitis, granulocytopenia, and thrombocytopenia. Overdose can cause liver injury. Severe hepatic and renal insufficiency is prohibited. Use with caution in children with liver disease or viral hepatitis, hepatic and renal insufficiency, severe cardiopulmonary disorders, and G-6-PD deficiency. Some compound preparations often contain “acetaminophen” as an ingredient, such as aminophenol alkylamine granules, aminophenol xanthamin granules, aminophenol mephedrone syrup, aminophenol mephedrone suspension and so on, but paracetamol and tylenol are single preparations. It is important to avoid repeating the medication when taking it. 2, Ibuprofen (Merrill): for children over 6 months of age. Single preparations include Merrill and Fen-Phen. The recommended dosage of ibuprofen for children is 5-10mg/kg every 6 hours, up to 4 times every 24h. Ibuprofen has a strong antipyretic effect, and the process of antipyretic may cause the body to sweat a lot, so when using ibuprofen to reduce fever, you need to pay attention to whether the child is dehydrated, insufficient intake, etc., and can be rehydrated through the vein if necessary. Ibuprofen is excreted through the kidneys and should be used with caution in patients with poor kidney function. Ibuprofen is safe to use according to the recommended dosage, and the common adverse reaction is gastrointestinal adverse reaction. children with G-6-PD deficiency can use “ibuprofen”. Lysine: It is the compound salt of aspirin and lysine, and its mechanism of action is the same as that of aspirin. Intravenous or intramuscular administration, reducing or avoiding the occurrence of gastrointestinal reactions, strong antipyretic effect, fast onset of action, slow and gentle, can be used as a common pediatric antipyretic drugs. It can be used for children who are prone to convulsions due to high fever and cannot take the drug orally. However, long-term application may induce Reye’s syndrome may even induce anaphylaxis and asthma severe attack. Used for intravenous antipyretic, the dose is generally 10-20mg/kg, 24 hours shall not be more than 4 times, the interval shall not be less than 4h. 4, aspirin: traditional antipyretic and analgesic, the World Health Organization does not recommend aspirin routinely used for pediatric fever, it is recommended to change to other categories of antipyretic drugs. China’s pediatrics has been basically not such drugs for fever, only for some special diseases, such as Kawasaki disease, rheumatic fever, juvenile arthritis and other treatments. 5, diclofenac: a new type of potent anti-inflammatory and analgesic drugs, it inhibits prostate synthesis and play its pharmacological role, with anti-rheumatic, anti-inflammatory, analgesic and antipyretic effect, analgesic, anti-inflammatory and antipyretic effect than indomethacin 2 to 2.5 times stronger than aspirin 26 to 50 times stronger than aspirin, strong, less adverse effects, small dose, small individual differences, for a variety of inflammation caused by fever. There is a view that children under 14 years of age are prohibited. 6, nimesulide: new non-steroidal anti-inflammatory, analgesic, antipyretic drugs, the pharmacological effect is to inhibit the activity of cyclooxygenase, blocking the biosynthesis of prostaglandin-like substances, leukocyte release of media and polymorphonuclear leukocytes oxidation reaction, so as to play the role of fever, anti-inflammatory effect, used for upper respiratory tract infections caused by fever, the effect can last for 6 to 8 hours. 2011, the media in February reported a number of fatal cases. In February 2011, the media reported a number of fatal cases, and then called it “life-threatening antipyretic”. 2011 May State Drug Administration issued a notice to limit the application of nimesulide, “prohibit its oral preparation applied to children under 12 years old”. Third, the application of clinical pediatric antipyretics principles Infants younger than 3 months are not recommended to use antipyretics, and can use physical cooling or the role of mild Chinese medicine to reduce fever. When the body temperature is lower than 38.5 ℃, generally do not need antipyretic drugs, can be used to physical cooling methods to reduce fever, with the exception of recurrent febrile convulsions. When the body temperature is higher than 38.5 ℃, safe antipyretic drugs can be used to treat, should avoid rapid fever, and be alert to possible dehydration, if necessary, intravenous rehydration. Ultra-high fever (> 41 ℃), will cause permanent damage to brain cells, and even other serious complications, such as pulmonary edema, cerebral edema, liver failure, etc., the serious case can lead to death, so it should be used to actively and effectively rescue measures to rapidly lower the temperature. Children with persistent high fever, if the single drug is not good enough to reduce fever, can be alternately applied to acetaminophen and ibuprofen. Alternate between the two drugs at least 2 hours apart. When alternating, the maximum number of times each medicine can be used is still 4 times a day. Drink plenty of fluids when taking medication to reduce fever, to speed up excretion and help take away heat from the body. At the same time, taking medication to lower the temperature at the same time also need to cooperate with physical means of lowering the temperature, which includes taking a warm bath, or wet hot towels to wipe the whole body, do not use alcohol to wipe, alcohol is easy to pass through the tender skin of children lead to alcohol poisoning. Avoid multiple antipyretic drugs used at the same time, increasing the risk of side effects. Fourth, the application of pediatric antipyretic drugs should pay attention to matters (1) pediatric thermoregulation center is not perfect, so pediatric fever should be based on physical cooling. (2) Fever is the body’s resistance to disease manifestation, should actively find the cause, treatment of primary diseases. (3) Master the active ingredients of various antipyretic and analgesic drugs, drug action characteristics, adverse reactions, contraindications, contraindications, etc., to prevent improper use of drugs to produce body damage. (4) According to the characteristics of pediatric antipyretics, the use interval of pediatric antipyretics should be reasonably mastered. (5) should be taken on time and in accordance with the amount, do not arbitrarily increase the dose or shorten the dosing interval. (6) During the antipyretic period, the child should be instructed to drink more water, so as not to cause defecation due to profuse sweating. (7) Generally use one antipyretic, and then consider combining them when the efficacy is really unsatisfactory. Recheck the body temperature about one hour after each dose to determine the effect of antipyretic. (8) Reasonable control of the duration of use, fever reduction. (9) During the use of drugs should pay attention to the toxic side effects of drugs, such as blood changes, gastrointestinal reactions, liver and kidney function impairment. (10) Severe, high fever persists in children, if necessary, can choose subhibernation therapy.